This application is based on and claims the priority under 35 U.S.C. xc2xa7119 of German Patent Application 100 07 019.1, filed on Feb. 16, 2000, the entire disclosure of which is incorporated herein by reference.
The invention relates to a tire filling station for filling pneumatic tires such as a motor vehicle tire in the form of a wheel/tire combination comprising a tire mounted on a wheel rim. The tire filling station includes a transport apparatus that transports the wheel/tire combination to a filling stand, including a tire filling dome or bell and an oppositely arranged support and seal arrangement, as well as means for moving at least one of the wheel/tire combination and the transport apparatus relative to each other in a direction perpendicular to the transport plane. A respective wheel/tire combination is received between the tire filling bell and the support and seal arrangement, which respectively contact and cooperate with the outer side walls of the tire, so as to fill air into the tire through an annular gap between the tire bead and the wheel rim.
In the high volume series production of motor vehicles on an assembly line, wheel rims and tires are respectively transported from different warehouse or supply locations by means of suitable transport apparatus, to a tire mounting production line, in which a respective tire is mounted on a respective wheel rim and then pressurized air is filled into the mounted tire at the desired tire air pressure. Next, the wheel/tire combination that has been produced in this manner is generally tested for its running characteristics or unbalance condition, and is generally also subjected to a balancing operation. The finished wheel/tire combination is then delivered from the tire production line to the assembly line for the complete motor vehicle, where the respective wheel/tire combinations are mounted on the motor vehicles.
A conventional tire filling station of the above mentioned general type is disclosed in U. S. Pat. No. 4,947,919. The conventional tire mounting and filling system according to this U. S. Patent essentially comprises a mounting station, a transport apparatus, and a tire filling station. In the mounting station, the tire is mounted on the wheel rim, and this combination is then transported in a pressure-less condition to the tire filling station by the transport apparatus. The transport apparatus comprises two chains on which the tire sidewalls of the wheel/tire combinations are supported. In the tire filling station, the transport apparatus is lowered or dipped down so that the respective wheel/tire combination comes to rest with its downwardly-facing side wall surface on a support plate.
In the arrangement shown in FIG. 5 of the above U. S. Patent, a tire filling bell or dome is arranged above the opposite or upwardly-facing side of the wheel/tire combination. In order to carry out the tire filling process, the tire filling bell is lowered, until the rim thereof presses the tire sidewall away from the wheel rim so as to form an annular gap or space between the tire side wall bead and the wheel rim. Then, the pressurized air filling of the tire is carried out through this annular gap. To achieve this, pressurized air flows from a pressurized air source through air passages in the support plate, through the sealed wheel rim inner space into the tire filling bell, and from there through the annular gap into the inner space of the tire. As the air pressure builds up within the tire, the air pressure inflates or expands the tire, whereby the air pressure pushes the tire sidewall and particularly the tire sidewall bead into sealing contact with the tire rim, while closing the above mentioned annular gap.
The above described conventional tire filling station is not suitable for use in tire mounting production lines in which wheels having respective wheel rims and/or tires of greatly varying sizes are to be mounted. In other words, such a known tire filling station is not readily adaptable for filling wheel/tire combinations of greatly differing sizes in succession, but instead is generally only suitable for the series production of a single size of wheel/tire combinations. Particularly, the capacity of the known tire filling station to handle wheel/tire combinations of different diameters is limited because the diameter of the support plate is limited or confined by the dimensions of the transport apparatus. Also, the size capacity of the known tire filling station is limited by the diameter of the tire filling bell. For these reasons, wheel/tire combinations having a larger diameter than intended for the respective tire filling station cannot easily be mounted or filled on such a tire filling station.
If the tire filling bell of the known filling station is equipped with a seal ring to seal against the side of the wheel rim during the filling operation, the filling station suffers the following additional disadvantages. The seal ring is subject to wear and damage, so that it requires a high degree of monitoring and maintenance. Wheel rims having any degree of running deviation of the lip or edge of the wheel rim can be crushed or bent by the seal ring pressing thereagainst. Especially when a seal ring is used in connection with wheel rims of present-day modern design, in which the major wall or bowl of the rim protrudes laterally outwardly beyond the rim lip, the seal ring will improperly contact the protruding bowl wall of the wheel rim at an angle relative to the wheel rim lip. For these reasons, it has been found in practice that such a tire filling bell has very little flexibility or adaptability for use with a tire size mix. All of these problems lead to additional efforts and costs in carrying out the tire filling process.
On the other hand, if the tire filling bell is not equipped with a seal ring, the major disadvantage is the substantially higher consumption and waste of pressurized air, because the entire interior space of the wheel rim must be filled with pressurized air during each filling cycle, in the manner as described above.
In view of the above, it is an object of the invention to provide an apparatus and a method for filling pneumatic tires, which is suitable for use with a broad variety of different wheel models or configurations and wheel sizes, even when such different wheel configurations or wheel sizes are successively to be processed in a mixed operation, in a fully automated tire filling and mounting system. The invention further aims to avoid or overcome the disadvantages of the prior art, and to achieve additional advantages, as apparent from the present specification.
The above objects have been achieved according to the invention in a first embodiment of a tire filling station for filling air into a wheel/tire combination including a tire mounted on a wheel rim. The tire filling station comprises a tire filling bell and a support and seal arrangement that are arranged respectively opposite one another, so as to receive the wheel/tire combination therebetween in a filling position while respectively contacting and cooperating with the side surfaces of the side walls of the tire, as well as a transport apparatus that transports successive wheel/tire combinations to and away from the tire filling station. The support and seal arrangement comprises a multi-part contact or support plate, of which the respective separate parts are movable apart and together with respect to each other, and particularly are arranged sealed against one another for carrying to out the tire filling process. At least one part of the multi-part support plate or the transport apparatus is respectively supported by a lifting device to be movable relative to the other in a direction perpendicular to the transport plane in which the successive wheel/tire combinations are transported by the transport apparatus.
The above objects have further been achieved according to the invention in a second embodiment, or according to a second feature of a tire filling station according to the invention, wherein the tire filling bell comprises at least two filling rings of different diameters, which are especially arranged concentrically and axially slidably relative to each other. Such an arrangement provides a telescoping construction of the filling rings, which is especially compact while still providing a long working range. Such an arrangement also allows adaptability to different size wheel rims by simply selecting the best-fitting one of the available tire filling rings for carrying out the filling operation.
The invention further provides a method for operating the above described tire filling station, as follows. A wheel/tire combination is transported by the transport apparatus to the tire filling station, where the wheel/tire combination is supported between the tire filling bell and the support and seal surface provided by the several parts or separate seal surfaces of the support and seal arrangement. Namely, once the wheel/tire combination has been transported to the tire filling station and supported in its proper position, then the transport apparatus and the wheel/tire combination are moved relatively apart from one another in a direction perpendicular or normal to the transport plane. Thereafter, the plural separate seal surfaces or support parts of the support and seal arrangement are moved together and joined or butted in a tightly sealed manner, while providing a seal against the downwardly facing side wall of the tire. A supply of pressurized air passes through an annular gap between the opposite upwardly facing side wall of the tire and the wheel rim, so as to fill air into the wheel/tire combination. After the complete filling of the wheel/tire combination, the several parts of the support and seal arrangement are moved apart from one another, and then the transport apparatus and the wheel/tire combination are again moved toward each other and brought into contact so that the wheel/tire combination is again supported on the transport apparatus and is then carried away from the tire filling station by the transport apparatus.
According to the second embodiment or second feature of the invention, a respective suitably sized one of the several filling rings making up the filling bell is selected dependent on the respective tire diameter of the wheel/tire combination to be filled. Namely, depending on the diameter of the wheel rim and the tire of the wheel/tire combination being filled, either the larger diameter outer filling ring, or the smaller diameter inner filling ring will be moved axially and downwardly into contact with the side wall of the tire, while the respective other filling ring remains retracted. The selected filling ring of the appropriate diameter protrudes downwardly beyond the other filling ring, so that the appropriate selected filling ring can achieve the necessary seal on the tire sidewall, while the other non-selected filling ring does not interfere with or hinder the filling operation.
The invention for the first time achieves the significant advantage that the range of application and the adaptability of tire filling systems can be significantly increased, especially in filling apparatus that do not use seal rings, in that the dimensions of the support and seal surfaces for the wheel/tire combination and/or the filling bell dimensions can be selected independently of the dimensions of the transport apparatus. In other words, the invention avoids the problem of the prior art, as discussed above, that the possible range of dimensions of the system components that support and seal the wheel/tire combination are limited to fit between clear center passage dimensions of the transport apparatus. This limitation or disadvantage of the prior art is overcome by the invention by providing that the seal surface and/or the filling bell is respectively embodied in a multi-part manner, so that these components can have a diameter that is independent of the configuration and the dimensions of the transport apparatus. In the context of seal-ring-free tire filling, a significant cost savings and process cycle time savings can be achieved also with regard to the known pallet transport systems in which each wheel/tire combination is allocated to its own individual pallet on which it is transported.
A particularly advantageous embodiment of the invention provides that the transport apparatus comprises two transport conveyor devices for supporting and transporting the wheel/tire combination, respectively on two opposite sides of the wheel center axis. Moreover in this embodiment, the support or contact plate of the support and seal arrangement comprises at least one central part or plate member arranged between the two transport devices, and at least one lateral part or plate member that is laterally arranged relative to the central plate member and is laterally movable to contact and seal against the central plate member. This embodiment is structurally simple and economical to manufacture.
A particularly compact construction of the inventive arrangement is achieved when the laterally joinable or sealable part of the support and seal arrangement is movable from an initial position between the two transport devices into the deployed sealed position. With such an arrangement the sliding or tilting movement of the laterally joinable part of the support and seal arrangement in a direction perpendicular to the transport direction is carried out from the inside or center toward the outside, i.e. outwardly.
A further embodiment of the invention provides for two lateral plate members or parts of the support and seal arrangement respectively arranged outwardly next to the two transport devices, whereby these two parts are laterally movable in a direction perpendicular to the transport direction from an initial separated position into the contacting or sealing position in which they are sealed respectively against opposite side edges of the central plate. This embodiment has the advantage that only two seal joints exist between the respective three parts of the support and seal arrangement, and the motion of the two outer parts is a simple sliding motion in a single plane.
In this embodiment, a further advantage is that the slidable outer parts or plates are supported not only on an outer portion thereof, but also on an inner portion thereof. In other words, when these outer plates are in their respective contacting positions sealed against the central plate of the support and seal arrangement, these outer plates bridge or span across an open area in which the respective transport conveyor device is arranged. At the same time, the outer and inner portions or edges of the outer plates are firmly supported, for example on corresponding outer or inner parts of the machine frame. Since the sliding displacement of the outer plates is only carried out when no load is being applied, i.e. in a load-free condition, the enormous air pressure forces arising during the tire filling process can be easily and reliably transmitted into the underlying machine frame or support structure without using costly or complicated slide bearings or the like for supporting the movable outer plates.